Dentifrice in paste, powder or liquid form is usually used for cleaning or embellishing of teeth. Generally, the dentifrice contains a mixture of a fine, grain-free polishing agent or abrasive for scouring and scrubbing the teeth and which will neutralize potentially deleterious or dangerous acids present in the gaps between the teeth. The latter object is invariably very difficult since bacteria penetrate deeply into the space between the teeth and convert remains of food, mainly sugar and starch, into lactic acid which has a particularly deleterious effect on the dentine.
Although the bacteria destroying effect of oxygen is well know, the incorporation of oxygen or oxygen releasing agents into toothpaste or powders, however, presents various problems. For example, the oxygen is often prematurely released thereby lowering or eliminating the efficacy of the dentrifice in addition to its limiting the shelf life thereof. For this reason the application of hydrogen peroxide separate from and in addition to a toothpaste or powder is often recommended. As used hereinafter the term oxygen containing agent shall include other bactericides and germicides that are non-toxic in the amount, and for the environment and use contemplated herein.
The present invention overcomes these disadvantages by providing a dentifrice containing an oxygen releasing agent such as hydrogen peroxide which is surrounded by envelopes which are rupturable upon mechanical manipulation of the sort occurring during the toothbrushing or cleaning operation.
The technique of microencapsulation per se is known in the art. For example, U.S. Pat. No. 3,686,701 disclosed a cosmetic applicator containing rupturable microcapsules which contain solvents for removal of nail enamel and perfume to mask the odor of said solvents. U.S. Pat. No. 3,691,270 discloses a cosmetic make-up removing composition incorporated in a flexible support throughout which are distributed microcapsules containing the cosmetic make-up removing or treating composition.